for 50–100 Years of Expected Sea-Level Rise

in Central California

Paul Alessio

Department of Earth Science

University of California, Santa Barbara

Abstract. Sea cliffs and beaches comprise a majority of the open wave-exposed coast of Central California. A major impact of climate change with rising sea levels is coastal erosion of beaches and sea cliffs. Influences of sea level rise will be manifested as changes in erosion rates of beaches and sea cliffs, ecosystem conditions, as well as changes in the fundamental interplays between natural and societal responses. El Niño has raised local sea levels in Central California by as much as 20–30 cm. This rise is equivalent to the projected sea-level rise for the region near the end of the 21st century.

The ongoing 2015–2016 El Niño year will be used as a surrogate for future sea-level rise by determining the impact of a 20–30 cm sea-level rise on open beach and coastal cliff ecosystems. This study is being conducted as an integrated study of the impacts of SLR on the Santa Barbara Coastline by the Earth Science, Marine Science, and Geography departments at UCSB. We plan to use a time series of terrestrial LiDAR (light detecting and ranging) scans before, during, and after winter 2015–2016 to assess the potential of natural and modified features to enhance coastal resilience and mitigate the potential impacts of extreme events along the open coast. By analyzing terrestrial LiDAR scans conducted at multiple sites along the Santa Barbara coast, before and after significant storm episodes, we will be able to difference the 3D scans to quantify physical and biological changes as a simple budget (input = output +/- change in storage). We also intend to develop simple models to evaluate the influence of physical and ecological factors on sea cliff, dune, and beaches to sea level rise. Results of this study will be used to engage in community partnerships with government and non-government organizations in developing values clarification and adaptive management options.

Adapting to sea level rise requires coastal communities to carefully weigh science and values. Science can predict change and inform solutions to protect coastal ecosystems and resources. Which solutions we choose will reflect our values. Local knowledge and values are key factors in working through specific dilemmas concerning what parts of coastal systems are to be protected from SLR—and how.